In a glowing review, Variety's Scott Foundas says the film "emerges as a surprisingly smart, gripping and imaginative addition to the zombie-movie canon." He continues: "Showing few visible signs of the massive rewrites, reshoots and other post-production patchwork that delayed its release from December 2012, this sleekly crafted, often nail-biting tale of global zombiepocalypse clicks on both visceral and emotional levels, resulting in an unusually serious-minded summer entertainment."

Foundas adds that director Marc Forster ("Quantum of Solace," "Monster's Ball") "handles the large-scale action here with considerable aplomb and much striking imagery," while Pitt, playing a former United Nations troubleshooter, is "a refreshingly human-scaled movie hero, with no outsized strength, agility or superpowers to help him win the day."

The Hollywood Reporter's Todd McCarthy is more measured. On one hand, he says, the film is "an immersive apocalyptic spectacle that tosses the viewer into the deep end of a global zombie uprising and doesn't let up until close to the end." All that action, however, comes at some narrative expense, with "Z" resembling "a bunch of impressive set pieces stitched together rather than a good story convincingly told."

McCarthy adds that fans of the original book by Max Brooks "will find much to be disappointed in," as the novel's multicharacter oral-history format has been "implausibly but understandably" reduced to a one-man show in which Pitt races to save the world.

Empire's Nick de Semlyen says "World War Z" "is slick, tense and hangs together fine, far from the disaster many predicted during its tortured birthing. But it's also just a little bit bland and generic. In particular, horror fans jonesing for grand-scale carnage are unlikely to come away entirely satisfied."

On the plus side, the "opening salvo is terrific," "the effects are handled well," and on the whole it "just about succeeds on its own merits."

Paul Bradshaw of Total Film says "Z" certainly looks the part: "There’s never been a more impressive horde of flesh-eaters on the big screen. Sprinting, gnashing, leaping and head-butting their way through civilization in a swarm of thousands, the zombie apocalypse finally looks big enough to be believable."

However, Bradshaw says the PG-13 film is "conspicuously bloodless" and "sorely lacking in heart (and with it, any genuine sense of danger)."

The Telegraph's Robbie Collin agrees with that last part, even calling upon the same turn of phrase: "There’s no heart to be found amid the guts," he writes. Instead, "What we get is a collection of moderately violent action set-pieces untroubled by humor or broader coherence."

Finally, IGN's Scott Collura says "Z" is "less a horror movie than it is a globe-spanning, international thriller, albeit one with zombies in it." He adds, "You could say this is the epic of zombie films … and it works for the most part." But the film's third act is "less effective," and there are visible "fracture lines" left behind by the production problems.

How the rest of the critics — and moviegoers themselves — react to the film remains to be seen. "World War Z" opens June 21.